如何在 Java 中将 JSON 字符串转换为 JSON 对象 (Gson)？答案

【问题标题】：How to convert a JSON String to a JSON Object (Gson) in Java?如何在 Java 中将 JSON 字符串转换为 JSON 对象 (Gson)？
【发布时间】：2018-04-23 22:26:24
【问题描述】：

我正在使用一个外部 API，其响应正文是 JSON 格式的字符串。我正在使用Gson 将字符串解析为 JSON 对象。但是，尝试在浏览器中显示对象时出现以下错误。

语法错误：JSON.parse：第 1 行第 1 列的意外字符 JSON 数据

这是我的代码：

控制器

    @RequestMapping("/player")
public JsonArray displayPlayer() throws Exception{


    String player = "PacSnackz";

    smite.createSession();

    String test = smite.getPlayer(player);

    JsonArray playerObj = new JsonParser().parse(test).getAsJsonArray();

    return playerObj;

}

惩戒类

      public String getPlayer(String player) throws Exception {
        if (!isSessionValid() && !createSession()) return "session null";
        return getURL(combine(new String[] {
                baseURL + "getplayer" + responseFormat,
                devID,
                getSignature("getplayer"),
                sessionID,
                getTimestamp(),
                player
        }, "/"));
}

这是 JSON 字符串的样子：

JSON 字符串

[{"Avatar_URL":"","Created_Datetime":"8\/16\/2016 4:30:14 AM","Id":9993055,"Last_Login_Datetime":"4\/23\/2018 8:47:56 PM","Leaves":3,"Level":17,"Losses":19,"MasteryLevel":1,"Name":"PacSnackz","Personal_Status_Message":"","Rank_Stat_Conquest":0,"Rank_Stat_Duel":0,"Rank_Stat_Joust":0,"RankedConquest":{"Leaves":0,"Losses":0,"Name":"League","Points":0,"PrevRank":0,"Rank":0,"Rank_Stat_Conquest":null,"Rank_Stat_Duel":null,"Rank_Stat_Joust":null,"Season":0,"Tier":0,"Trend":0,"Wins":0,"player_id":null,"ret_msg":null},"RankedDuel":{"Leaves":0,"Losses":0,"Name":"Duel","Points":0,"PrevRank":0,"Rank":0,"Rank_Stat_Conquest":null,"Rank_Stat_Duel":null,"Rank_Stat_Joust":null,"Season":0,"Tier":0,"Trend":0,"Wins":0,"player_id":null,"ret_msg":null},"RankedJoust":{"Leaves":0,"Losses":0,"Name":"Joust","Points":0,"PrevRank":0,"Rank":0,"Rank_Stat_Conquest":null,"Rank_Stat_Duel":null,"Rank_Stat_Joust":null,"Season":0,"Tier":0,"Trend":0,"Wins":0,"player_id":null,"ret_msg":null},"Region":"North America","TeamId":0,"Team_Name":"","Tier_Conquest":0,"Tier_Duel":0,"Tier_Joust":0,"Total_Achievements":28,"Total_Worshippers":510,"Wins":35,"ret_msg":null}]

我正在使用 Spring Boot Java 和 Google 的 Gson 库。我也调查过杰克逊，也没有运气。

【问题讨论】：

我不确定 JSON Array 是否被普遍认为是有效的 JSON 根对象。我可以看到 Gson 库如何认为您的 JSON 字符串无效。

标签： java json rest spring-boot

【解决方案1】：

我想出了答案。诀窍是将 Player 设置为一个数组。对于其他对象，我使用 for 循环返回多个对象。在本例中，它设置为 0，因为只有一名玩家。

@RequestMapping("/player")
public Player displayPlayer() throws Exception{


    String player = "PacSnackz";

    smite.createSession();

    String test = smite.getPlayer(player);

    Gson gson = new Gson();

    Player[] playerObj = gson.fromJson(test, Player[].class);

    return playerObj[0];



}

【讨论】：